Calendar.



(No Modem F. B. MUELLER.

c A L E N D A B Q rApplic'axion led Sept. 29, 1 900. I

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Patented Dec. 4,1900.

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GA L E N D A R.

(Application Bled Sept. 29. IQOOJ (No Model.)

, cal diametrical section of Fig. 1. y

plan view of the intermediate disk of the cal-l NITED STATES PATENT OFFICE.

CALENDAR.

SPECIFICATION forming part of Letters Patent No. 662,954, dated December 4, 1900.

Application iled September 29, 1900. Serial No. 31,522. (No model.)

To a/ZZ whom it may concern/.-

Be it known that I, FREDERICK BOY MoEL- LER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a new and useful Calendar, of which the following is a specication.

This invention relates to calendars in geueral, and more particularly to the class of perpetual calendars, one object of the in vention being to provide a construction wherein the days vof any month of any year from 1752 may be correctly shown, the number of years being limited only by the dimensions.

A further object of the invention is to provide a construction wherein the numbers of the leap-years are separately grouped and i wherein the month-names of January and February will be automatically shifted to correspond to the leap-years, it being understood that in the leap-years January has the same calendar as July, while in other years it has the same calendar as October, this arrangement eliminating the necessity for mental calculation for leap-years.

Further objects and advantages of the invention will be evident from the following 'de- Scription. y

In the drawings forming a portion of this specification and in which like numerals of reference indicate similar parts in the several views, Figure l is a top plan view showing the complete calendar set to show the month of September, 1900. Fig. 2 is a verti- Fig. 3 is a endar. Fig. 4 is a plan View showing the bottom disk of the calendar.

Referring now to the drawings, the calendar comprises three disks a, b, and c, of which the lower disk is provided with a num ber of curved rows d of numbers which represent the days of Weeks, these curved rows being arranged spirally, with theirinner ends resting upon the periphery of a common circle e. The numbers are also separated by division-lines f into a plurality of columns which lie radially of the disk. The numbers in each spiral row begin with 1, and the numbers in four successive rows run to 3l, inclusive; the next five rows run to 30, inclusive; the next two rows run to 29,

inclusive, and the last two rows run to 28, inclusive. There are thus thirteen spiral rows, and the inner ends thereof are spaced siX columns apart, as shown in Fig. 4: of the drawings, whereby by beginning with l in any row it is possible to count to 7, then drop to the number 'under l and count to 14, then drop to the next number under l and count to 21, and continue this dropping until the last end of a spiral row is reached. In other words, it is possible to divide the entire group of numbers into a series of segmental groups wherein portions of the several rows of numbers will be utilized to present a succession of numbers running CG l), 28,77 QQ, (30,77 (631,7) the case may be. The number of segmental groups possible is limited by the number of columns of numbers, which is ninety-one.

To present each single segmental group by itself, the disk c is provided and has a segmental opening g therein, which opening is of sufficient width to uncover seven columns of numbers. At the minor end of the segmental opening are marked the initials of the days of the week, beginning with Sunday. The ninety-one possible segmental groups of numbers correspond to the days of the months throughout the limits of the calendar above expressed; but some means must of course be provided for showing the proper group when a certain definite month is to be represented. For this purpose the intermediate disk b is provided and has printed upon its upper face adjacent its edge which projects from under the edge of the disk c the names of the months of November, June, September, and April in one group, the months of December, July, October, May, August, and March in a second group, and February standing alone. The disk a has a pointer h, which is adapted for alinement with the month-names successively. January has the same calendar as October in common years and the same as July in leap-years, and for this reason January is represented twice, once in each of its two positions, but spaced dierently from the edge of the disk b, so that one may be covered andthe other uncovered at proper times. To effect this covering and uncovering7 disk c has a segmental recess z' TOO in its edge to uncover the January name opposite to October, anddirectly adjacent thereto is a segmental. opening j, positioned -to uncover the second January name when the first January name is covered. There is also a secondY February name,'which is' normally covered by the disk c and at which time the first February name is exposed through the recess 7c in the edge of disk c, and when disk cis moved to cover the first February name it uncovers the second Febru-Y proper years, two groups of numbers Z and m f with the two naughts' OO on disk c.

are represented upon the disk c, each number of one group representing thelast two figures of the date of each common year, while each number of the second group represents the last twofigures of eachvleap-year date. Upon the protruding edge of disk b are marked 17, 18, and 19, represen ting the three centuries for which the calendar is used.

The `operation of the calendar is as follows: Supposing that the month of September, 1900, is to be shown, then the disk b is rotated to bring the number 19 upon its edge in line This will give the opening g the proper position 'with respect to the year-date, and the disk a is then rotated to bring the pointer h opposite to the month-name September, which action will bring the proper group of numbers on disk a beneath the segmentai opening g for exposure therethrough, as shown in Fig. l of the drawings. It will be noted that when the disk a is moved to bring the century-numbersi. e., 17, 18, and 19-opposite the common year group of figures t the outer February name is exposed and the January name opposite to October is exposed. When the disk b is moved to bring the centu ry-n umbers opposite to the leap-year group m, then the inner February name is exposed and the outer one is covered, and at the same time the outer January name is covered and the January name opposite to July is exposed. Thus in adjusting the calendar for Februarytor January of a leapyear the group of numbers exposed through the opening g is entirely different from the group exposed when the calendar is adjusted for a common year. It will thus be seenthat for any month of any year Within the limits of the calendar there is no calculation necessary, but instead the disks are shifted to give the proper exposure through the opening g at all times, while the calendar will also show the month-name and the year-date to which the exposed day-numbers relate.

It will 'be understood that in practice any suitable materials and proportions may be used and that various modifications of the specific construction shown may be made without departing from the spirit ofv the invention,it"being also understood'that the several disks are pivotally connected in axial alinement. Also it will be noted that the disk?) has an opening n for registration with wtheopening g to permit exposure of the monthnumbers or day-numbers of the months.

What is claimed is l. -A calendar comprising a plate having represented thereon a group of the last figures of the common-year dates of a century and a separate group of the last figures of the leap-year dates of a century, a second plate "having the first gures of several centuries marked thereon and adapted for alinement with the figures ofthe groups of the first plate interchangeably, the second plate having also month-nam es thereon, and a third plate below the second plate and having a plurality of columns of figures thereon and having a pointer for alinement Withthe month-names interchangeably, the several plates bein g pivotally connected for adj ustment with respect to each other, and the first two plates having openings for alinement to expose groups of figures of the third plate.

2. A calendar comprising a plate having represented thereon a group of the last figures of the common-year names of a century and a separate groupof the last figures of the leap-year dates of a century, a second plate having the first figures of several centuries marked thereon and adapted for alinement with the figures of the groups ofthe first plate interchangeably, the second plate having also l month-names thereon, the naines of certain months being repeated in dierent positions, and a third plate below the second plate and having a' plurality of columns of figures thereon and having a pointer for alinement with the month-names interchangeably, the first plate being formed to expose different of the repeated month-names as the century first gures are shifted from one to the other of the groups of last century figures, the several plates being pivotall y connected and the first and second plates having openings therein for alinement to expose groups of gures on the third plate to correspond to the century and year indicated by the first and second plates.-

In testimony that I claim the foregoing as my own I have hereto affixed my signature in the presence of two witnesses.

FREDERICK BOY MOELLER.

IOO 

